PORT-AU-PRINCE, Haiti_Haiti's civil aviation authority has grounded the country's largest domestic airline after two of its flights were forced to make emergency landings within two weeks, officials said Thursday.

The National Civil Aviation Office said the restriction on Caribintair's flights would remain until investigators determine why the twin-engine Cessna Caravan planes were forced to make hard landings in rural areas on Tuesday and on Aug. 31.

"We know this decision will have consequences on air traffic but ... we cannot continue to have incidents of this nature," agency director Jean Lemercq Pierre told private broadcaster Radio Metropole.

Four passengers and the pilot were injured in Tuesday's emergency landing, which left the 13-seat plane upside down and with a badly damaged tail. Both accidents happened during flights from the capital of Port-au-Prince to the northern city of Cap-Haitien.

On Thursday, officials from Cessna and the U.S. National Transportation and Safety Board arrived in Haiti to assist local investigators conducting a review of Caribintair's operations, airline spokesman Jean Cyril Pressoir said.

"We're confident all the planes went through the proper maintenance cycle," Pressoir said.